LS4 Oil Pressure
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LS4 Oil Pressure I have an 08 impala SS that I rebuilt the engine in a year ago. After about 9,000-10,000 miles had low oil pressure warning come up and I parked it. No noises when parked but 3 days later I started it to drive it into the garage and I had a lot of valve train noise. Found out the the oil pump internal bypass was stuck open a bit and the first and fourth cam bearings had slid out of place causing no resistance or lubrication. Rebuilt engine again, everything rechecked, machined as needed, cleaned, etc. First 6,000 miles were good, then oil pressure warning again. Not the best decision but I said the heck with it and kept driving it. A month later oil pressure was back to normal ranges. A month after that, low oil pressure again. I drive a variety of places including highway and some city. After a little over three months with no explanation as to why it says low pressure I have no engine noise. I have used three different sensors which all say the same, I have used a manual gauge which reads lower yet, 0 at warm idle. Still no engine noise. Before anyone suggests it, the oil filter screen below the sensor is currently not installed. I have found no metal of any kind during oil changes. I'm looking for out of the box ideas as I have already stumped many mechanics I know that have done it for years. Regardless I'm going to have to pull the motor back out to fix whatever is wrong. At this point I am leaning towards the camshaft retainer plate. I know from the rebuilds that it had little or no seal sticking up anymore. I'm chalking it up to inexperience and believing that its internal so what does it matter, also considering that the oil pump has no gasket on these engines. Let me know if you think this is where you think I should begin and what else to check while its semi apart. Thanks in advance.
I don't have an answer, but that's a lot of work to be guessing what it might be. I would contact a reputable LS builder like Texas Speed or another one of the vendors here and pick their brain. I would think 0 at warm idle would seize, and would try another gauge. With the problems you have had an oil pressure gauge should be installed in the cabin permanent now. Good luck , post back you findings.
